The overall objective of the research being proposed is to develop in more quantitative detail the structural factors which influence the spectral properties, particularly the circular dichroism, of polypeptides when the chain is in statistical conformation (random coil). As a corollary the reality of certain new ordered structures that have been postulated, such as the extended helix and double hydrogen bonded helix, will be investigated by non-optical methods. The general method of attack is to establish the conformation of a given polypeptide, which possesses a particular type of circular dichroism spectra, by the standard methods of polymer physical chemistry. The crucial quantity to be determined is the characteristic ratio which can be obtained from intrinsic viscosity and osmotic pressure virial coefficients. Auxiliary information in regard to bond structure and isomerization will be obtained by means of high resolution proton nmr and 13C nmr. At the present time comparison between the nmr and optical spectra are being emphasized.